What's Not: Have trouble with Android tablets. No indication when charging is full or the battery is depleted.

Reviewed by Tong Zhang

The mophie juice pack powerstation duo is an external battery pack that can charge two mobile devices at the same time via USB. The 6000 mAh battery can output up to 2.1 amp power to charge smartphones, cameras and iPads. It's compact and weighs only 7.2 ounces. The juice pack powerstation duo comes with a USB cable that you can use to charge the battery via AC or computer or use the cable to charge your device with a standard micro USB port.

Design

The juice pack powerstation duo is compact and easy to carry in your gear bag or even in a purse, measuring at 2.28 x 4.30 and x 0.78 inches. The rectangular battery pack has two full USB ports that allow you to charge two devices from it at the same time, and a micro USB port for recharging the battery pack. The juice pack powerstation duo is super easy to use with no controls. Plug your devices in, the battery will just start charging. The battery pack does have a push button that you can use to check the battery level indicated by four LED lights on the front.

For the holiday season, mophie released white versions of their battery packs. And if you have a white phone or tablet, you can match the color with the new white juice pack powerstation duo. While the black version has a soft touch matte surface, the new white version has a shiny surface. The build quality is excellent with stainless steel band covering the side of the battery, providing structural support.

Features

The mophie juice pack powerstation duo has 6000 mAh battery that's good for 500 full charging cycles. The battery can take input of 5V, 0.5 to 2.1 amp and outputs up to 2.1 amp power and that means it has enough output power to charge any smartphone as well as most tablets, though in our tests it worked mostly with just iPads. The large capacity battery is an excellent companion for your smartphones as it can provide 2-3 times of a full charge for a smartphone and charges it quite fast. The battery charged our iPhone 5 from 20-percent to full less than two hours and only used a little over a quarter of a full charge of the battery pack. It takes more effort for the juice pack powerstation duo to charge tablets, the bigger the tablet, the longer it takes to charge. The juice pack powerstation duo charged the iPad mini from very low power to full in about 4 hours and that depleted the battery pack. With the new iPad, the juice pack powerstation duo took two hours to deplete its battery to add about 35 percent of battery power. Duo charging splits battery power as well as slows down charging time.

You can use the included USB cable to charge the juice pack powerstation duo via either a computer or an AC adapter. The battery pack charges slowly via a computer but faster via AC. It takes about 4 hours to charge the battery pack from zero to full power but it will take at least 6 hours via computer. As with other mophie battery packs, the juice pack powerstation duo has built-in safety features such as short circuit and overcharge protection. The battery doesn't have pass through power however, this means you can't charge the battery while it's charging your devices.

The built-in LED lights on the juice pack powerstation duo is handy for checking the battery level and they flash when you first plug your device into the battery pack, then the LED will turn off automatically after 90 seconds. One feature we wished the mophie had, that we found on other battery packs, is an alert via the LED or the device when the device is fully charged.

We tested the juice pack powerstation duo with several smartphones including iPhone models as well as Android smartphones including Motorola, Samsung and HTC Android smartphones. We tested the battery pack with several tablets as well, it had no trouble charging any iPad models but it didn't work with the Samsung Galaxy Note 10.1 and the Lenovo IdeaTab S2110.

Conclusion

The mophie juice pack powerstation duo is a very useful tool for the road warriors who need extra power for their smartphone, tablet, handheld gaming device and camera. The battery pack outputs enough power for most mobile devices except certain Android tablets. But if you use the battery pack for primarily smaller devices and iPad models, you're good to go. The battery can also charge two devices at once and has LED indicator for battery level. Now it comes in either black or white to match your favorite iDevice color. The white version will be available in Apple Stores nationwide beginning Oct. 31, 2012.